In machine tools, a variety of chucking means are used in the production of machine parts. For small and relatively simple workpieces, standard chucks are used, optionally in combination with special chucking jaws and various accessories. However, for the production of large pieces, such chucking means are less suitable.
For workpieces, which in view of their size and shape cannot be locked into the usual chucking fixtures, special expensive chucking means specifically adapted to the workpiece must be provided.
In machine tools, in particular in numerically controlled machines, for the direct or indirect chucking of workpieces, hold-down bolts are used, which hold-down bolts are inserted into T-shaped or dove-tailed grooves of the machine tables.
In the case of a variable chucking device for the holding of different workpieces according to Patent No. DE-GM 1 983 371, a workpiece may be clamped individually on both sides by chucking blocks, or two workpieces, in the form of double chucking, may be clamped between the chucking blocks. An intermediate piece is fixedly set into the T grooves of the base plate and is adjustable in height. A disadvantage of this arrangement is that the chucking device cannot be expanded to hold several workpieces.
From Patent No. DE-GM 1 815 274 a T-shaped grooved vise is known, in which sliding clamping jaw blocks and their pressure pieces are lined up on a tie rod located in the T groove of the table. One end of the tie rod is equipped with a guide head, while a threaded nut is located on the other end of the tie rod projecting from the T groove. The tightening of the nut displaces the pressure pieces and sliding blocks. By providing intermediate jaws and the sliding blocks, which are also drilled for the passage of the tie rod, several workpieces may be clamped in simultaneously. The clamping of the workpiece is highly time-consuming and very accurate clamping is only possible under certain conditions.
In the production of a large series of workpieces, to a certain extent specially shaped and adapted clamping means may be used on the machine table, so that, for example, three workpieces may be mounted simultaneously. A disadvantage is that such special clamping means require more space, together with long setup times. Furthermore, the loss of time while changing tools is unavoidable.
A common disadvantage of all of these clamping means is that the surface of the machine table usually cannot be utilized in an optimal manner.